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93 Explorer 4.0 OHV ecu change

Discussion in 'Stock 1991 - 1994 Explorers' started by Eduardox88, July 12, 2018.

^^Searches ExplorerForum.com^^





  1. Eduardox88

    Eduardox88 New Member

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    Hi,

    I'm new here and I need your experience to solve a problem I'm presenting right now.

    I'm just going to swap my bronco II 2.9 for an Explorer 93 4.0. Let me explain the story from the beginning:

    I bought a 93 4x4 explorer very cheap from a yunkyard that didn't run. It has auto trans. It didn't have the ECU and I took the risk and buy it however. The guy told me a mechanic was trying to start the engine with no luck and that he said to him the crankshaft sensor was bad. The steps I did before trying to start were:

    1- Bought a new original crankshaft(I installed it) and a Manual ECU (cause my bronco is manual and I didn't want the check engine light on because of auto trans solenoids,etc).
    2-Changed oil and oil filter (old oil looked good and clean but I preferred to change it)
    3-Put clean fuel (tank was empty) then I remove fuel filter hose and turned on the pump until I saw clean fuel coming out.
    4-Install a radiador and belt (didn't have them)
    5- Change spark plugs and spark plugs wires
    6-Repair a broken wire from one O2 sensor, connected the fuel pressure regulator vacuum hose.
    7- Turned the engine Manually to assure it turns without problem
    8- Connect the power for distribution box, the battery and try to start, AMAZINGLY the engine started but it stalled right away. I need to rev a little bit so it stays running.

    Problem:
    1- It missfire a lot and throw black smoke.
    2-Put the scanner and throw me those codes:
    117 - ECT sensor is/was low or grounded - ECT
    122 - (O,M) TP low (possibly grounded or open circuit) - TPS
    112 - (O,M)
    Intake Air Temperature (IAT) sensor is/was low or grounded - IAT
    513 - (O)
    Replace processor (PCM) (internal failure)
    565 - (O)
    Canister Purge 1 solenoid/circuit failure - Solenoids
    556 - (O,M)
    Fuel pump relay primary circuit fault - Power / Fuel Pump Circuits

    Verifications:
    1-I removed the oil cap while it was running and it doesn't throw nothing, seems like engine compression is good also engine sounds good.
    2-All fuses needed for starting the engine are good.

    Question: It's possible that using a manual ECU in an auto explorer (same year explorer) can cause this problem and codes? I'm afraid about 513 code

    Next steps:
    1-I will install a new TPS,ECT and IAT sensors
    2- Check continuity from ECU pin 49 and 46 to TPS plug (93 ECU diagram show those are the 5v reference to those sensors)

    Sorry for all this text but I wanted to explain the situation clearly so you guys can help me with this.

    Every help will be appreciated.

    ECU Diagram 93.gif
     
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  3. 410Fortune

    410Fortune River season Staff Member Moderator

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    You cannot use a 5 speed computer to control an automatic truck yes it will/can cause all sorts of codes ot SOUNDS to me like you have the wrong PCM attached to the wiring harness

    What PCM did you use to start it? MUST be from a 93, not a 91-92 or a 94
     
  4. Eduardox88

    Eduardox88 New Member

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    Thanks for your reply, I'm not trying to use the auto transmision. I don't care, I'm gonna put the engine in my bronco 2 which has a manual transmission.

    The explorer from which I took the ECU is 93 manual, the one from which I will take the engine is 93 auto.
    I just want to start the engine and see it run smoothly then I will remove and install in my Bronco ii
     
  5. 92exp4x4

    92exp4x4 Elite Explorer

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    If the explorer is a 93, and you have a 93 PCM installed, it should run fine. You would get the codes associated with the auto trans solenoids not being there, but everything else should work fine as long as it matches the emissions system.

    Just make sure the PCM you have is or is not for an EGR equipped engine. If the engine has a cam sensor and EGR, it is Cali emissions. If not, then it's federal emissions. All 94s were Cali, 91-92 were federal across the board. 93 could be had either way.

    The 513 code concerns me as well, you might want to spring for a reman PCM, matching your build once it's complete. Also, I highly recommend doing a compression check to verify your engine, as well as just running it.
     
  6. Eduardox88

    Eduardox88 New Member

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    Thanks for your reply.

    I got assured that both doesn't use neither EGR or CAM sensor so this won't be a problem.

    Also I forgot to mention is, right now the switch is always in on position so I use to unplug one battery terminal every time I need to cut of the power to ECM relay. Can this cause the ECU register a 513 code as I'm unplugging it a lot?
     
  7. Eduardox88

    Eduardox88 New Member

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    Hey guys,

    Just for update.

    I changed TPS,ECT and IAT and the problem continues, I don't know but I feel a little better. Well at the end I removed the injectors I will take them to a place for check, I think the problem is there. One test was unplug the spark plug #6 and after that the injector #6 and I didn't feel a change.

    I post again when I test

    Thank you guys
     
  8. Eduardox88

    Eduardox88 New Member

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    Hey, I have an update but it's bad news...

    Today I installed 6 remanufactured injectors and the problem continues BUT I measure the 5volt reference signal from ECU to sensors (TPS,IAT and ECT and found no 5 volt reference but all the wires have continuity to the ECU pin.

    This point me to check the ECU, maybe I bought it damaged because in yunkyard you buy as is.

    Now I need to take it for a check.

    Will update when I have new info.

    Thanks
     
  9. Eduardox88

    Eduardox88 New Member

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    Hi guys,

    Well, problem solved!

    The problem was the ECU, it had some filters inside damaged, I took it to a ECU repair shop and they fixed it.

    I was little scared because when I installed it I got the 5 volt reference but it didn't want to start jajajaja, the day I removed the ECU for repair purpose the engine started and when it was repaired didn't start jajaja.

    At the end the no start condition was caused by wet spark plugs with gas, I removed and cleaned them and it started right away.

    I want to say thank you to everyone that commented here. Every comment was useful for me.

    'm asking myself yet why this truck was junked if everything works, trainny,differentials, engine, etc

    Thank you!
     

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